When the foot is positioned on the glass of a scanner, the heel area and the metatarsal area suffer a deformation (flattening), which causes the scanned image not to be suitable for making an insole or orthoses that can be perfectly adapted to the entire sole of the foot in order to spread the load during walking.
In order to solve this problem a tool that allows distributing an even stress across the entire sole of the foot, similar to walk on the sand, has been designed. For this purpose, an elastic mesh has been suspended on two bars adjustable in height and width, thus by using a handle it is possible to increase or decrease the stress. The system allows varying the rubber stress, as it includes two roulettes allowing through their rotation increasing or decreasing the stress of the membrane and thus adapting it to the patient weight. Furthermore, with the feet image taken by the scanner and the membrane, the automated double-sided machining is achieved based on the image taken, using a turner and the developed software, thereby the insole can be obtained with or without holes for allowing transpiration.
The system is capable of utilizing a plurality of cameras for obtaining images, allowing it to be used for obtaining images from any body part, including full body, in order to develop prostheses.
Currently, and as for systems for obtaining a plantar image, there is no scanner on the market that provides the described possibility therein, using the aforementioned elastic mesh. Double-sided machining insoles do exist, but it is a manual, almost crafted, method.
Vision measurement equipments usually have built therein a camera with a laser generator constituting the triangulation measurement probe itself. The laser generator fits at its end an optic that allows converting the laser spot beam in a range of beams making up a flat geometry, and with a preselected fixed opening angle for covering the object width. The laser light projection from this plane onto the piece or object subjected to be measured generates a light line reflected therefrom, which is taken by the camera, being desirable that only appears the previous light source in the capture site, so as not to obtain spurious points outside the laser plane wherewith the measurement is made. Additionally, in this type of configuration there is a relative movement between the probe and the object to be measured. A synchronized position and image sequence allowing spatially reconstructing all points of the taken lines corresponding to successive cuts of the laser plane is obtained by using the object measured during the movement.
As a prior stage to the measurement, a method for calibrating the camera-laser probe and characterizing the movement axis with respect to thereof has to be performed, using an object pattern with well-known geometry. These systems are called sweep laser triangulation systems and are usually used to digitize the sole of the foot. The fixed and relative arrangement between the camera's optical axis and the laser plane, as well as their relative position with respect to the surface during the sweep, make possible to obtain an increase or decrease of slenderness on the line taken by the camera, leading to a equipment accuracy loss, or a geometric information loss of certain areas due to absence of obtained points. The movement control and its synchrony with the camera have also associated errors.
Furthermore, the incorporation of a single camera in these equipments raises the problem that during the sweep of a free surface with more or less pronounced concavities or convexities, as the sole of a human foot, the line concealment can be produced. To avoid this, a variant consists of arranging the laser perpendicular to the surface of two cameras, such that the line always appears in one of the two images. But these equipments pose a number of problems:                To integrate a mechanical component subject to wear, inaccuracy sources and reliability problems. The relative accuracy positioners (ball screws or belt transmission with a ruler or linear encoder) significantly increase the equipment price.        A laser diode is used as a light generator and calibrated measuring element, which raises the problem of its useful life, and the need for performing adjustments and recalibration by qualified personnel at least at the end of its useful life.        The patient has to keep the foot in the possible most static position during long time for obtaining the image and position sequence. Any slight movement involves direct errors in the geometry that may go unnoticed.        The aligned arrangement of the cameras and the laser along the longitudinal axis of the foot does not offer an optimal perspective to digitize its side edges up to a certain height, because of its sharp curve in certain areas of the foot sides.        